Leaving aside that finding Satoshi isn't a particularly laudable goal, isn't the original Bitcoin client open source? It's almost certainly easier to detect programming style from source code than from binaries.
The bitcoin client would be the training set.
In the ccc talk, the author actually talk about this. But she mentioned that their primary suspect doesn't have any code samples online, and they left it at that.
Their code should be online, but I am not sure what exactly is there though.
Depending of how much of Satoshi's fingerprint is left and how early they started to version control the code.
That was the first thing that came to my mind too :)